What is Zoladex® (goserelin)?

Zoladex® (goserelin) is a hormone therapy used to treat advanced breast cancer in both premenopausal and perimenopausal people with breast cancer that is hormone receptor-positive (HR+). It is also used to treat certain forms of prostate cancer and endometriosis.1-3

Goserelin is an implant that is injected under the skin. It slowly dissolves, releasing its medicine between doses.1-3

What is the ingredient in Zoladex?

The active ingredient in Zoladex is goserelin.1-3

How does goserelin work?

Many breast cancers are classified as HR+, meaning they have receptors on the surface of their cells where hormones like estrogen can attach. When the hormones connect with these receptors, they can fuel the growth of the cancer cells and lead to them growing and spreading.

Goserelin is a luteinizing hormone-releasing hormone (LHRH) agonist. The pituitary gland secretes gonadotropin, which stimulates the production of estrogen by the ovaries. LHRH agonists like Goserelin stops the pituitary gland from releasing gonadotropin. This reduces the amount of estrogen in the body, which slows the growth and breast cancer cells and kills them.1-3

What are the possible side effects of goserelin?

The most common side effects of goserelin include:1,3

Goserelin may also cause serious side effects, including:1-3

  • Temporary worsening of symptoms of breast cancer, including bone pain, during the first few weeks of treatment
  • High blood sugar levels
  • Heart problems, including heart attack and stroke
  • High levels of calcium in the blood (hypercalcemia)
  • Injury at the injection site
  • Allergic reaction

Tell your doctor if you have any new or worsening side effects while taking goserelin.

These are not all the possible side effects of goserelin. Talk to your doctor about what to expect or if you experience any changes that concern you during treatment with goserelin.

Things to know about goserelin

Goserelin should cause menstruation to stop. If your period continues, tell your doctor.1-3

Goserelin can harm an unborn baby. If you can become pregnant, you should use birth control during treatment and for some time after the last dose of goserelin. You should also not breastfeed during treatment with goserelin and for some time after the last dose. Talk to your doctor about your options for birth control and breastfeeding while taking goserelin.1,3

Before beginning treatment for breast cancer, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of goserelin.

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Written by: Editorial Team | Last reviewed: March 2021